WO2008016015A1 - Display device, method for generating four or more primary color signals, and program causing computer to execute processing for generating four or more primary color signals - Google Patents

Abstract

It is possible to provide a display device capable of faithfully reproducing a color indicated by a video signal including a component of a negative level and performing display of a sufficiently wide color reproduction range. The display device performs display by using n (n is a natural number not smaller than 4) primary colors. The display device includes a video signal conversion unit which receives m (m is a natural number smaller than n) primary color signals corresponding to m primary colors and converts the m primary color signals into n primary color signals corresponding to the n primary colors. The n primary colors contain the primary colors in the relationship of complementary colors against one of the m primary colors. When the color component corresponding to one of the m primary colors is at a negative level, the video signal conversion unit generates n primary color signals so that the luminance of the primary color in the relationship of the complementary colors is higher and the luminance of the primary colors other than the primary color in the relationship of the complementary colors is lower than when a color component corresponding to one of the primary colors is zero.

Description

 Specification

 Display device

 Technical field

 The present invention relates to a display device that performs display using four or more primary colors.

 Background art

 Currently, various display devices are used for various purposes. In a typical display device, one pixel is composed of three sub-pixels that display the three primary colors of light, red, green, and blue, which enables color display.

 However, the conventional display device has a problem that a displayable color range (referred to as “color reproduction range”) is narrow. Figure 13 shows the color reproduction range of a conventional display device that displays using the three primary colors. FIG. 13 is an xy chromaticity diagram in the XYZ color system, and a triangle having apexes at three points corresponding to the three primary colors red, green, and blue represents the color reproduction range. In the figure, the surface colors (see Non-Patent Document 1) of various objects that exist in nature, as revealed by Pointer, are plotted with X marks. As can be seen from FIG. 13, there are object colors that are not included in the color reproduction range, and some display colors cannot be displayed on a display device that displays using the three primary colors. The color reproduction range of the display device is compared with the standard color reproduction range (EBU ratio, EBU (European Broadcasting Union) and NT≥> C (National Television System Committee)). It is often expressed by NTSC ratio).

 [0004] As described above, since the conventional display device has a narrow color reproduction range, even if the imaging device can record a wide V and range of colors, some colors (that is, out of the color reproduction range). (Color) cannot be displayed. Therefore, it is necessary to perform signal processing for correcting a color outside the color reproduction range of the display device to a color within the color reproduction range at the signal processing stage on either the imaging device side or the display device side. More specific description will be given below.

[0005] For example, in general television broadcasting, a YCrCb signal including a luminance signal Y and two color difference signals Cr and Cb is transmitted. The transmitted YCrCb signal is converted into an RGB signal containing components indicating the luminance (ie, gradation) of red, green, and blue, and the display device uses this RGB signal. Display based on the signal.

 [0006] The YCrCb signal itself is capable of expressing colors outside the EBU standard color reproduction range if all possible signal levels are used. YCrCb signals that express colors outside the EBU standard are simply displayed. When converted to RGB signals, at least one of the components corresponding to red, green, and blue becomes negative. Since conventional display devices cannot display colors outside the EBU standard, when RGB signals containing negative level components are input, negative level components are treated as zero (referred to as clipping). ) Can be corrected to a color within the EBU standard that can be displayed by the display device.

 [0007] For example, when a YCrCb signal indicating cyan (indicated by a point R- in Fig. 16) that is not an EBU standard as shown in Fig. 16 is converted into an RGB signal, the component corresponding to red is negative. Level, and so to speak, a signal indicating a negative gradation is generated. Since such a scene cannot be displayed on a conventional display device, the component corresponding to red is clipped and treated as zero, so that cyan within the EBU standard (indicated by point R0 in FIG. 16! /, Display after correcting to). Such correction processing enables display on a conventional display device, but there is a problem that the original object color cannot be expressed because the displayed color is a corrected color.

 [0008] On the other hand, in recent years, a method for increasing the number of primary colors used for display to four or more has been proposed in order to widen the color reproduction range of display devices.

 [0009] For example, in Patent Document 1, as shown in FIG. 14, there are six sub-pixels R, G, B, Ye, C, and M that display red, green, blue, yellow, cyan, and magenta. A liquid crystal display device 800 in which the pixel P is configured is disclosed. The color reproduction range of this liquid crystal display device 800 is shown in FIG. As shown in Fig. 15, the color reproduction range represented by a hexagon with six points as vertices corresponding to the six primary colors almost covers the object color. Thus, the color reproduction range can be widened by increasing the number of primary colors used for display. In the present specification, display devices that perform display using four or more primary colors are collectively referred to as “multi-primary color display devices”. Patent Document 1: Special Table 2004-529396

Non-Patent Document 1: MR Pointer, 'The gamut of real surface colors, Color Research and Application, Vol. 5, No. 3, pp. 145—155 (19 80)

 Disclosure of the invention

 Problems to be solved by the invention

[0010] However, the conventional broadcasting standard is based on the premise that a display device that performs display using three primary colors is used! /. Therefore, the multi-primary color display disclosed in Patent Document 1 is used. Even if the device is used simply, the color reproduction range is wide! /, And! /, And the characteristics of the multi-primary color display device cannot be used, and the color reproduction range can be sufficiently wide and displayed. What! /

[0011] For example, if a signal indicating a negative gradation is clipped in the same manner as in the past, it is possible to achieve only the same color reproduction range as that of a conventional display device, and a component at a negative level. A method to faithfully reproduce the colors indicated by video signals including multi-color display devices has not yet been established!

[0012] The present invention has been made in view of the above problems, and an object of the present invention is to faithfully reproduce a color indicated by a video signal including a component at a negative level, and to achieve a sufficient color reproduction range. An object of the present invention is to provide a display device capable of performing a wide display.

 Means for solving the problem

 [0013] The display device of the present invention is a display device that performs display using n (n is a natural number of 4 or more) primary colors, and m (m is smaller than n! /, A natural number) primary colors. A video signal converting unit that receives a corresponding m primary color signal and converts the m primary color signal into an n primary color signal corresponding to the n primary colors, wherein the n primary colors are included in the m primary colors; When the color component corresponding to the one primary color of the m primary color signals is at a negative level, the primary color that is in the relationship between the one primary color and the complementary color is included. The luminance of the primary color in the complementary color relationship is higher than that in the case where the color component corresponding to the one primary color is zero, and the luminance of the primary colors other than the primary color in the complementary color relationship is lower. The n primary color signals are generated.

 [0014] According to an embodiment, the video signal conversion unit generates a color matching color signal by performing color matching on the m primary color signal, and linearly combines the color components of the color matching color signal. As a result, each color component of the n primary color signal is generated.

[0015] According to an embodiment, the color matching conversion color signal corresponds to the one primary color. A color component including a color component and corresponding to the one primary color is assigned a coefficient used for the primary combination to each of the n primary colors! / Among the coefficients assigned to the color components corresponding to one primary color, the coefficient for the primary color having the complementary color relationship and the coefficient for the primary color other than the primary color having the complementary color relationship have different signs. .

 According to an embodiment, the video signal conversion unit generates each color component of the n primary color signal by linearly combining the color components of the m primary color signal.

 [0017] According to an embodiment, a coefficient used when performing the primary combination is assigned to each of the n primary colors! /, To the color component corresponding to the one primary color. Among the coefficients assigned to the color component corresponding to the one primary color, the coefficient for the primary color related to the complementary color and the coefficient for the primary color other than the primary color related to the complementary color are mutually The sign of the sign is different.

 [0018] According to an embodiment, a pixel including a plurality of sub-pixels is provided, and each of the plurality of sub-pixels displays a corresponding one of the n primary colors.

 According to an embodiment, the certain primary color is red, and the primary color complementary to the certain primary color is cyan.

 [0020] According to an embodiment, the one primary color is green, and the primary color complementary to the one primary color is magenta.

 [0021] According to an embodiment, the certain primary color is blue, and the primary color complementary to the certain primary color is yellow.

 In one embodiment, the n is 5 and the m is 3.

 [0023] According to one embodiment, the five primary colors are red, yellow, green, cyan, and blue, and the video signal conversion unit is a color component corresponding to red of the five primary color signals. Is at a negative level, the luminance of cyan, which is complementary to the red color, is higher than that when the color component corresponding to red is zero, and the luminance of primary colors other than cyan is lower. Generate the five primary color signals.

[0024] According to an embodiment, the five primary colors are red, yellow, green, cyan, and blue, and the video signal conversion unit is a color component corresponding to blue of the five primary color signals. Is at a negative level When the color component corresponding to the blue color is zero, the brightness of the yellow color that is complementary to the blue color is higher and the brightness of the primary colors other than yellow is lower. Is generated.

 [0025] The method of the present invention is a method for generating n primary color signals corresponding to the n primary colors for display using n (n is a natural number of 4 or more) primary colors, Includes a conversion step of receiving m primary color signals corresponding to m primary colors (m is a natural number smaller than n) and converting the m primary color signals into the n primary color signals, wherein the n primary colors are including a primary color that is complementary to one primary color among the m primary colors, and the converting step includes a negative level of a color component corresponding to the one primary color of the m primary color signals. When the color component corresponding to the one primary color is zero, the luminance of the primary color other than the primary color having the complementary color relationship is higher than that when the color component corresponding to the one primary color is zero. Generating the n primary color signals so that the It is characterized by

[0026] The program of the present invention causes a computer to execute generation processing for generating n primary color signals corresponding to the n primary colors for display using n (n is a natural number of 4 or more) primary colors. The generation processing includes a conversion step of receiving m primary color signals corresponding to m primary colors (m is a natural number smaller than n) and converting the m primary color signals into the n primary color signals. The n primary colors include a primary color that is complementary to a primary color of the m primary colors, and the conversion step includes the one primary color signal of the m primary color signals. When the color component corresponding to the primary color is at a negative level, the luminance of the primary color in the complementary color relationship is higher than when the color component corresponding to the one primary color is zero, and the complementary color The brightness of the primary colors other than the relevant primary colors Characterized in that it comprises the step of generating said n-primary signal in Kunar so.

 The invention's effect

[0027] According to the present invention, when a color component corresponding to one primary color of the m primary color signal is at a negative level, the color component corresponding to one primary color is smaller than when the color component corresponding to the one primary color is zero. Generates n primary color signals with increased brightness of primary colors that are complementary to one primary color. Here, n is a natural number greater than or equal to 4, and m is a natural number smaller than n. The color component is at a negative level Since colors (ie, colors outside the m primary color reproduction range) can be expressed, it is possible to display in a wide and / or color reproduction range.

Brief Description of Drawings

FIG. 1 is a diagram showing a display device according to an embodiment of the present invention.

 FIG. 2 is a diagram showing four pixels among the pixels of the multi-primary color panel according to the embodiment of the present invention.

 FIG. 3 is an XY chromaticity diagram in an XYZ color system showing a color reproduction range of a display device according to an embodiment of the present invention.

 FIG. 4 is a diagram showing the luminance ratio of the five primary colors when displaying EBU-R, G, B, Y, C, Μ, and W colors according to the embodiment of the present invention.

 FIG. 5 is an xy chromaticity diagram in an XYZ color system representing a color having a negative color component according to an embodiment of the present invention.

 FIG. 6 is a diagram showing signal processing when an RGB signal according to an embodiment of the present invention does not include a negative level color component.

 FIG. 7 is a diagram showing signal processing when an RGB signal includes a negative level color component according to an embodiment of the present invention.

 FIG. 8 is a diagram illustrating a relationship between a color in which any one of red, green, and blue color components is at a negative level and a pointer color according to the embodiment of the present invention.

 FIG. 9 is a diagram showing an RGB signal having a negative red color component level according to an embodiment of the present invention.

 FIG. 10 is a diagram showing an RGB signal having a negative green color component level according to an embodiment of the present invention.

 FIG. 11 is a diagram showing a method for calculating coefficients corresponding to color matching conversion color signals according to an embodiment of the present invention.

 FIG. 12 is a diagram illustrating a method for calculating a coefficient corresponding to a color signal having a negative color component according to an embodiment of the present invention.

[Fig. 13] An xy chromaticity diagram in the XYZ color system, with triangles having vertices at three points corresponding to the three primary colors red, green, and blue, representing the color reproduction range. FIG. 14 is a diagram showing a liquid crystal display device in which one pixel P is configured by six sub-pixels R, G, B, Ye, C, and M that display red, green, blue, yellow, cyan, and magenta. .

 15 is a diagram showing a color reproduction range of the liquid crystal display device shown in FIG.

 FIG. 16 is a diagram showing a color in which the component corresponding to red is at a negative level.

 Explanation of symbols

[0029] 100 display device

 110 Video signal converter

 11 1 Matrix converter

 112 3-primary / multi-primary color converter

 120 multi-primary color panel

 121 pixels

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the present invention will be described using a liquid crystal display device as an example. However, the present invention is not limited to a liquid crystal display device. tion Electron-emitter Display) and the like.

 FIG. 1 is a diagram showing a liquid crystal display device 100 according to an embodiment of the present invention. The display device 100 includes a video signal conversion unit 110 that converts a received video signal to generate a multi-primary color signal, and a multi-primary color panel 120 that performs display according to the multi-primary color signal. The video signal conversion unit 110 includes a matrix conversion unit 111 and a three primary color / multi-primary color conversion unit 112.

 [0032] The display device 100 performs display using five primary colors. The video signal converter 110 receives the three primary color signals corresponding to the three primary colors, and converts the three primary color signals into the five primary color signals corresponding to the five primary colors.

 [0033] In this example, the three primary colors corresponding to the three primary color signals (hereinafter, these three primary colors are collectively referred to simply as "three primary colors") are red, green, and blue. The five primary colors corresponding to (hereinafter, these five primary colors are collectively referred to as “5 primary colors”) are red, green, blue, yellow, and cyan.

In the present specification, the components corresponding to the respective primary colors of the 3 primary color signal and the 5 primary color signal are expressed as “ This is called “color component”. The color component substantially represents luminance. In the present embodiment, the three primary color signals include a red component, a green component, and a blue component, and the five primary color signals include a red component, a green component, a blue component, a yellow component, and a cyan component.

 [0035] The five primary colors include primary colors that are complementary to one of the three primary colors. For example, cyan is a complementary color of red and yellow is a complementary color of blue. The dominant wavelength of red is about 610 to 635 nm, the dominant wavelength of green is about 520 to 550 nm, the dominant wavelength of blue is about 470 nm or less, and is the complementary color of cyan.The dominant wavelength of cyan is about 475 to 515 nm and is the complementary color of blue. The dominant wavelength of yellow is about 560 to 585 nm. The display device 100 may have magenta (green complementary color) as a primary color. In this case, the auxiliary main wavelength of magenta is about 495 to 565 nm.

 [0036] The multi-primary color panel 120 includes a plurality of pixels arranged in a matrix. FIG. 2 shows four pixels 121 among the pixels of the multi-primary color panel 120. Each pixel 121 is defined by a plurality of sub-pixels as shown in FIG. Specifically, the plurality of sub-pixels that define the pixel 121 display a red sub-pixel R that displays red, a green sub-pixel G that displays green, a blue sub-pixel B that displays blue, and yellow. Yellow sub-pixel Ye and cyan sub-pixel C displaying cyan. In the example shown in FIG. 2, these five sub-pixels are arranged in one row and five columns in the pixel 121.

 [0037] There are various formats of video signals received by the display device 100 including those currently proposed. For example, as shown in FIG. 1, sRGB, BT.709, BT.601, sYCC, adobeRGB, DCI, xvYCC and BT.

 [0038] Of the formats illustrated in FIG. 1, sRGB, BT.709, and BT.601 are video signal formats that include only colors within the color reproduction range equivalent to EBU. When the display device 100 receives a video signal in any of these formats, the display device 100 displays the color within the color reproduction range of the EBU.

 [0039] Further, adobeRGB and DCI are video formats that can express colors outside the EBU color reproduction range by taking the chromaticity points of the three primary colors wider than the EBU color reproduction range.

[0040] On the other hand, sYCC, xvYCC ,: BT. 1361 is a video signal format including chromaticity points of the three primary colors of the EBU, but also including colors outside the color reproduction range of the EBU by having a negative value. The display device 100 receives a video signal (also referred to as a high color gamut signal) of these formats. In this case, it is possible to faithfully represent colors outside the EBU color reproduction range, which is not limited to colors within the EBU color reproduction range.

 [0041] As already described, at least one color component is negative in the three primary color signals indicating colors outside the color reproduction range (hereinafter simply referred to as "reference range") defined by a standard (for example, EBU). Is at the level of When the color component corresponding to one primary color of the three primary color signals is at a negative level, the video signal converter 110 has a complementary color relationship than when the color component corresponding to the one primary color is zero. The 5 primary color signals are generated so that the brightness of the primary colors in is increased. For example, when the red component is at a negative level, the five primary color signals are generated so that the luminance of cyan, which is a complementary color, is high, and the luminance other than cyan is low. By performing such signal processing, colors outside the reference range can be displayed faithfully. The reason for this will be explained with reference to FIG.

 FIG. 16 shows a color R− indicated by the three primary color signals whose red component is at a negative level and a color R0 indicated by the three primary color signals whose red component is zero. As shown in Figure 16, the color R0 when the red component is zero is located on the boundary of the reference range, while the color R- when the red component is at the negative level is the reference range. To the cyan side (that is, in the direction of increasing the saturation of cyan).

 [0043] For the three primary color signals whose red component is at a negative level, if clipping is performed in the same manner as before (that is, the red component is treated as zero), the color displayed on the multi-primary panel 120 will have zero red component. This is the same as the color R0 indicated by the three primary color signals. On the other hand, by generating the 5 primary color signals so that the cyan brightness is higher than when the red component is zero, the color displayed by the multi-primary panel 120 is in the direction of increasing the saturation of cyan. It can be shifted in the direction from R0 to R— and in the opposite direction, and can display the color R— faithful to the received three primary color signals. At this time, since the red component changes from 0 to a negative level, the overall luminance is reduced by the negative level. Therefore, it is necessary to reduce the luminance other than cyan in consideration of the increased luminance of cyan. is there.

[0044] As described above, the color indicated by the three primary color signals having a negative color component corresponding to a certain primary color deviates from the reference range in the direction in which the saturation of the complementary color of the primary color increases. Yes. Therefore, the brightness of the primary color that is in a complementary color relationship is higher than when the primary color component is zero. In order to compensate the luminance of the negative level, and to reduce the luminance of the primary colors other than the primary colors that are in the complementary color relationship, the five primary color signals are generated, thereby faithfully reproducing the received three primary color signals. Various colors can be displayed.

 The video signal conversion unit 110 in the present embodiment first generates a transient color signal (referred to as a “color matching color signal”) by performing color matching of the three primary color signals. Here, the uniform color conversion refers to converting a combination of color components expressing a certain color into a combination of other color components without changing the expressed color.

 In addition, the video signal conversion unit 110 generates each color signal of the five primary color signals by multiplying each color component of the equal color conversion color signal by a coefficient and adding the result. That is, the video signal conversion unit 110 generates the respective color components of the five primary color signals by linearly combining the respective color components of the color matching conversion color signals.

 Here, with reference to FIG. 3, the color reproduction range of the display device 100 using the five primary colors will be described. Figure

 3 is an xy chromaticity diagram in the XYZ color system. The positions on the chromaticity diagram of the five primary colors used by the display device 100 are represented by MPC—R, G, B, Y, C. A pentagon having five points corresponding to the five primary colors of red, green, blue, yellow, and cyan represents the color reproduction range of the display device 100. The triangle with the three vertices corresponding to the three primary colors of red, green, and blue represents the above-mentioned reference range. This standard range is expressed based on the technical standards regarding the color of color television receivers established by the EBU. Red, green, blue, yellow, cyan, and magenta located at the boundary of the reference range are represented as EBU—R, G, B, Y, C, and Μ. The color reproduction range of the five primary colors surrounds the reference range, and the display device 100 can faithfully display colors outside the reference range.

[0048] Since the liquid crystal display device 100 performs color display using the five primary colors, naturally, when displaying a certain color, the five sub-pixels are each lit with a predetermined luminance. Fig. 4 is a table showing an example of the ratio of the luminance of the five primary colors when displaying EBU—R, G, B, Y, C, Μ, and W colors. Here, EBU-W represents white. In this example, each of EBU—R, G, B, Y, C, and Μ is basically represented by three primary colors located near the five primary colors. For example, EBU-R is expressed as the ratio of ^ [? 1 ^ 1 luminance 1.015, ^ [? Ji: 6 luminance 0.010, ^? じ 丫 luminance 0.094. The this In this way, the predetermined luminance ratio becomes a coefficient used when generating each color component of the five primary color signals by the linear combination described later.

Next, a process for generating a video signal on the photographing side will be described.

 [0050] The imaging device (not shown) receives light indicating the color of the subject (represented by tristimulus values (X, Y, Ζ) in the XYZ color system), performs color space conversion, and outputs a signal L , L and L are generated.

 R G B

 The color space conversion is expressed by, for example, the following (Equation 1) in the xvYCC standard.

 [Number 1]

 (Formula 1)

 [0051] Next, by performing photoelectric conversion (inverse gamma conversion) shown in (Equation 2), the signals L, L

 R

 , L generate signals E, E, E.

 B R G B

E = l.099L ⁰⁴⁵ -0.099 for L≥0.018

 E = 4.500L for 0.018> L> -0.018

E = -l.099 (-L) ⁰⁴⁵ + 0.099 for -0.018≥L

 (Formula 2)

 [0052] By calculating the signal E when -0.018≥L, negative: a certain color component can be included in the video signal.

 [0053] Next, the color signal conversion shown in (Equation 3) is performed to generate signals E, E, E force signals E, E, E.

 R G B Y Cb Cr

 E = 0.2126E + 0.7152E + 0.0722E

 E 0. 1146E -0.3854E + 0.5000E

 E = 0.5000E -0.4542E --0.458E

 (Formula 3)

[0054], E force luminance signal Y and color difference Generate signals Cb and Cr.

 Y = 219Ε + 16 16≤ Y≤235

 Cb = 224E + 128 1≤ Cb≤254

 Cr = 224E + 128 1≤ Cr≤254

 (Formula 4)

 The generated luminance signal Y and color difference signals Cb, Cr are transmitted as, for example, video signals and received on the display device side.

 Next, video signal processing on the display device side will be described.

The matrix conversion unit 111 included in the display device 100 performs color signal conversion shown in (Equation 5), and converts the received luminance signal Y and color difference signals Cb and Cr into RGB signals R, G, and B.

 [Equation 2]

ソ ,

Seo

(Formula 5)

 Here, the chromaticity diagram shown in FIG. 5 is referred to. When the actual color of the subject (X, Y, Ζ) = (0. 233, 0. 379, 0. 345), this color is located at the boundary of the reference range. At this time, the RGB signal obtained from (Equation 5) is (R, G, B) = (0, 180, 138), and since it is not at the negative level of the color component force S, it can be displayed as it is.

 [0059] However, when the actual color of the subject is out of the reference range, for example, (X, Y, Ζ) = (0.151, 0.33 37, 0.341), it is obtained from (Equation 5) RGB signals are (R, G, B) = (—lll,

180, 138), and since the red color component is at a negative level, it cannot be displayed as it is, and signal processing is required to faithfully represent this color.

 With reference to FIG. 6 and FIG. 7, signal processing for faithfully expressing the color of an RGB signal including negative level color components will be described.

[0061] Figure 6 shows the signal processing when the RGB signal does not contain negative level color components, Figure 7 shows the signal processing when the RGB signal contains negative level color components.

First, with reference to FIG. 6, a process for generating five primary color signals when the RGB signal does not include a negative level color component will be described.

[0063] RGB signal R G B is converted from matrix converter 111 (Fig. 1) to three primary colors / multi-primary colors converter 11

 in in in

 Input to 2. The bar graph on the left side of Fig. 6 shows the red component R contained in the RGB signal.

 in Indicates the level of green component G and blue component B (indicating red, green, and blue brightness respectively)

 in in

 The The three primary color / multi-primary color conversion unit 112 converts the RGB signal R GB into a uniform color.

 in in in

 Generates a color conversion color signal including white component DW, yellow component DY, and red component DR.

[0064] As can be seen from the figure, the levels of the red component R, green component G, and blue component B of the RGB signal are shown.

 The level of the lowest blue component B in the in in in level is the white component DW of the color conversion signal.

 in

 Become a level. Also, the level of the second lowest green component G and the level of blue component B

 in in

 The difference is the level of the yellow component DY of the color conversion signal, and the highest red component R

 The difference between the in level and the level of the green component G is the level of the red component of the color conversion color signal.

 in

 Become. Here, the type of the color component included in the force color conversion color signal in which the color conversion color signal including the white component DW, the yellow component DY, and the red component DR is generated is not limited to this. The color conversion color signal is the red component R, green component G, and blue of the input RGB signal.

 in in Red component DR, Green component DG and Green component DG corresponding to the three primary colors according to the magnitude relationship of color component B

 in

 It can contain seven types of color components: blue component DB, cyan component DC corresponding to these complementary colors, magenta component DM and yellow component DY, and white component DW which is an achromatic component.

[0065] The three primary color / multi-primary color conversion unit 112 generates each color component R G B Y C of the five primary color signals by linearly combining the respective color components DW DY DR of the equal color conversion color signals.

out out out out Coefficients Wr Wc Yr Yc Rr Rc used for the primary combination are assigned in advance to each color component DW DY DR of the color conversion color signal for each of the five primary colors used for display. Here, the coefficient used for the primary combination represents the ratio of the luminance of each of the five primary colors assigned in advance to each color component of the color matching conversion color signal. For example, Rr Rc is a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a yellow sub-pixel for the red component DR. It shows the ratio of luminance that each pixel and cyan sub-pixel should bear. Specifically, (Rr, Rg, Rb, Ry, Rc) = (1.015, 0.000, 0.010, 0.094, 0.000). As shown in (Equation 6) below, these coefficients are multiplied by the white component DW, yellow component DY, and red component DR of the color matching conversion color signal to obtain the sum (primary combination). 5 Color components R to C of the primary color signal are determined.

 out out

 R = DRX Rr + DYXYr + DWXWr

 out

 G = DR X Rg + DYXYg + DW XWg

 out

 B = DRX Rb + DY XYb + DW XWb

 out

 Y = DR X Ry + DYXYy + DW XWy

 out

 C = DR X Rc + DY XYc + DW XWc

 out

 (Formula 6)

 [0066] The three primary colors / multi-primary color conversion unit 112 includes color components R to C corresponding to the five primary colors, respectively.

 out out

The five primary color signals are generated and output to the multi-primary color panel 120, and the multi-primary color panel 120 displays colors according to the received five primary color signals.

[0067] Next, with reference to FIG. 7, a process of generating five primary color signals when the RGB signal includes negative level color components will be described. In the example shown in Fig. 7, the blue component B is at a negative level. Blue

 in

 A color whose color component B is at a negative level is a color belonging to region 1 shown in FIG. Figure 8 is red

 in

 Color and pointer with negative color component R, green component G, or blue component B

 in in in

 It is a figure which shows the relationship with a color. Regions 1 to 3 are regions outside the reference range. A color whose level of blue component B is negative is a color belonging to region 1. Red component R level is negative in in

 The colors that belong to area 2 are Colors with a negative green component G level belong to region 3.

 in

 Color.

 [0068] When the blue component B is at a negative level, the luminance of yellow, which is complementary to blue, increases.

 in

 By generating the 5 primary color signals, colors belonging to area 1 can be displayed.

[0069] Referring again to FIG. The bar graph shown on the left side of Fig. 7 shows the levels of the red component R, green component G, and blue component B (representing red, green, and blue luminances, respectively) in the RGB signal.

 is doing. The level of the color component of blue component B is negative. 3 primary color / multi-primary color converter 112

 in

 , RGB signal R, G, B by color conversion, blue component NB, yellow component DY,

in in in A color conversion color signal including the red component DR is generated. The procedure for color matching is as described with reference to FIG. The level of blue component B (which is at a negative level) of the RGB signal

 in

 Since the blue color component NB of the color matching color signal remains unchanged, the level of the blue color component NB is also negative.

 [0070] The three primary color / multi-primary color conversion unit 112 generates the respective color components R G B Y C of the five primary color signals by linearly combining the color components NB DY DR of the equal color conversion color signals.

 out out out out Each color component NB DY DR of the color conversion color signal is pre-assigned with the coefficient Br Be—Yr Yc Rr Rc used for the primary combination for each of the five primary colors used for display! / . Among the coefficients Br Be— assigned to the blue component NB of the color conversion color signal, the coefficient By— corresponding to the primary color yellow that is complementary, and the coefficient Br Bg— Bb corresponding to the primary colors other than yellow — Signs of positive and negative are different from Be-.

 [0071] As shown in (Equation 7) below, each color component R C of the five primary color signals is obtained by performing a linear combination.

 out ou is decided.

 t

 R = DRXRr + DYXYr + NBXBr-out

 G = DRXRg + DYXYg + NBXBg-out

 B = DRXRb + DYXYb + NBXBb- out

 Y = DRXRy + DYXYy + NBXBy-out

 C = DRXRc + DYXYc + NBXBc- out

 (Formula 7)

 [0072] In (Equation 7), the product of the red component DR and the corresponding coefficient (DRXRr DRXRg "'), the product of the yellow component DY and the corresponding coefficient (DYXYr DYXYg'-'), and the blue component

The product of the NB and the corresponding coefficient (NB X Br-NB X Bg) is added! In the combination of coefficients corresponding to the blue component NB, the By coefficient has a negative value, and the other primary color coefficients have positive values. (Negative value) X (Negative value) = (Positive value), so the level of yellow component Y of 5 primary signals is higher by NBX By—

 out

 5 which is higher than when the blue component B is zero.

 in

A primary color signal can be generated. By increasing the brightness of yellow, it belongs to region 1 shown in Color can be faithfully reproduced. In addition, since the blue component NB is a negative value in (Equation 7), the brightness of the primary colors other than yellow is reduced by NB X Bx— and the blue component B is zero.

 in

 5 primary color signals can be generated such that the brightness of the primary colors other than yellow is lower than that of By reducing the brightness of the primary colors other than yellow, the power S can be reproduced more faithfully to reproduce the colors belonging to region 1 shown in FIG.

 [0073] In the description with reference to FIG. 7, a force showing an example in which the level of the blue component B is negative is shown in FIG.

 in

 Similarly, when the level of the red component R is negative, the luminance of cyan, which is the complementary color of red,

 in

 Generates 5 primary color signals that become higher and lower in brightness for the primary colors other than cyan. Figure 9 shows an RGB signal with a negative red component R level.

 in

 FIG. 10 shows an RGB signal having a negative green component G level. Magenta

 in

 In the case of 5 primary colors, the present invention is not applicable! /. However, when a magenta is used as a primary color as in a display device using 6 primary colors, the brightness of magenta, which is a complementary color of green, increases. Therefore, the 5 primary color signals should be generated so that the brightness of the primary colors other than magenta is low.

[0075] Next, an example of a method for calculating coefficients used in the above-described linear combination will be described with reference to FIGS.

 Of the color components included in the color matching conversion color signal, the coefficient for the color component at the positive level can be calculated as described with reference to FIG. On the other hand, the coefficient for the color component at the negative level can be calculated as follows.

 [0077] FIG. 11 is a diagram illustrating a method of calculating a coefficient corresponding to the blue component NB at a negative level. Chromaticity of yellow (MPC—Y) that is displayed when only the yellow sub-pixel that displays yellow, the complementary color of blue, is lit at the brightness corresponding to the highest gradation (hereinafter referred to as “all lit”) x , Y and brightness Y are

 x = 0. 465

 y = 0. 522

 Y = 0. 486

 (Formula 8)

 It is. The level of each color component R, G, B of the RGB signal to display such chromaticity x, y and lightness Υ yellow is

in in in R = 0. 668

 in

 G = 0.498

 in

 B = 0

 in

 (Formula 9)

 Power S is assumed. The level of each color component R, G, B of the RGB signal is such a value

 in in in

 In this case, the color component levels of the red component DR, yellow component DY, and blue component NB of the color matching conversion color signal are

 DR = 0. 170

 DY = 0. 498

 NB = -0. 058

 (Formula 10)

 It becomes. By multiplying the coefficient assigned to the red component DR (the coefficient shown in the EBU-R row shown in Fig. 4) by the level of the red component DR, the red component as shown in (I) of Fig. 11 is obtained. The luminance of the five primary colors MPC—R to C for displaying the component DR is obtained.

 [0078] Similarly, by multiplying the coefficient assigned to the yellow component DY (the coefficient V, shown in the EBU—Y row shown in FIG. 4) by the level of the yellow component DY, ( As shown in II), the brightness of the five primary colors MPC—RC for displaying the yellow component DY can be obtained.

 [0079] Fig. 11 (IV) shows the luminances of the five primary colors MPC-R to C when only the yellow sub-pixel is lit. Here, the brightness of the five primary colors MPC—R to C for displaying the red component DR, the brightness of the five primary colors MPC—R to C for displaying the yellow component DY, and the blue component NB are displayed. This is the total power of the five primary colors MPC—R to C. This corresponds to the luminance of the five primary colors MPC—R to C when all the yellow sub-pixels are fully lit. ) And (II) are subtracted to obtain the luminances of the five primary colors MPC-RC for displaying the blue component NB, as shown in (III) of FIG. That is, (III) = (IV) one ((1) + (II)) holds.

[0080] Since the luminance shown in (III) corresponds to the luminance when the level of the blue component NB is 0.058, dividing the luminance shown in (III) by 0.058 gives the level of the blue component NB. The luminance (reference value) when is 1 is obtained as shown in (V). The luminance ratio shown in (V) It is none other than the ratio of the five primary colors for displaying the tonal blue color. From the value shown in (V), it can be seen that as the absolute value of the level of the blue component NB increases, the luminance of yellow as a complementary color increases and the luminance of the other primary colors decreases. Since the sign of the level of the blue component NB when performing the linear combination is negative, the value shown in (VI) is obtained by inverting the sign of the value shown in (V), and the coefficient for the blue component NB in the negative level It can be. In this way, the coefficient for the blue component NB at the negative level (coefficient for linear coupling) can be obtained.

 [0081] In the above description, the level of each color component of the input RGB signal is assumed from the chromaticity and brightness when only the yellow sub-pixel is fully lit, and the coefficient for the blue component NB is calculated backward. However, of course, the coefficient for the blue component NB can be calculated back from the chromaticity and brightness of the color displayed in other lighting states.

 It should be noted that the coefficient used when the level of the red color component is negative can be obtained in the same procedure as described above based on the luminance when only the cyan primary color is lit.

 [0083] Note that the five primary color signals may be generated by performing linear combination of the color components of the RGB signal without performing color matching. With reference to FIG. 12, an example of a method for calculating coefficients used in such a linear combination will be described. FIG. 12 is a diagram illustrating a method for calculating the coefficient corresponding to the blue component NB at the negative level.

 [0084] Each color component R, G, B of the RGB signal has coefficients Rr to Rc in in in which linear combination is performed.

 , Gr to Gc, Br— to Be— are assigned in advance. As shown in the following (Equation 11), by performing the linear combination, the respective color components R, G, B, Y, and C of the five primary color signals are determined.

 out out out out out

 R = R X Rr + G X Gr + NB X Br- out in in

 G = R X Rg + G X Gg + NB X Bg- out in in

 B = R X Rb + G X Gb + NB X Bb- out in in

 Y = R X Ry + G X Gy + NB X By- out in in

 C = R X Rc + G X Gc + NB X Bc-out in in

 (Formula 11)

 [0085] Referring to FIG. 12, the level of each color component of the RGB signal is

 R = 0. 668

 in

G = 0.498 B = 0

 in

 (Formula 12)

 Is the same as the method shown in Fig. 11. Next, in the method shown in FIG. 12, the coefficient assigned to the red component R (shown in the EBU-R row shown in FIG. 4).

 in

 Coefficient) and the level of the red component R, the red component as shown in (I) of FIG.

 in

 Minutes MPC—R to C brightness for displaying the minute R is obtained.

 in

 [0086] Similarly, the coefficient assigned to the green component G (shown in the EBU-G row shown in Fig. 4).

 in

 The coefficient is multiplied by the green component G level, as shown in (II) of Fig. 12.

 in

 The brightness of the five primary colors MPC—R to C for displaying the green component G is obtained.

 in

 [0087] The luminances of the five primary colors MPC-R to C when only the yellow sub-pixel is lit are shown in (IV) of FIG. Here, the brightness of the five primary colors MPC—R to C for displaying the red component R, and green

 in

 The total power of the five primary colors MPC—R to C for displaying the color component G and the five primary colors MPC—R to C for displaying the blue component NB. Therefore, by subtracting the luminance shown in (I) and (II) from the luminance shown in (IV), (III) in Fig. 12 As shown in Fig. 5, the luminance of the five primary colors MPC—RC for displaying the blue component NB is obtained. That is, (III) = (IV) one ((1) + (II)) holds.

 [0088] Since the luminance shown in (III) corresponds to the luminance when the level of the blue component NB is 0.058, dividing the luminance shown in (III) by 0.058 gives the level of the blue component NB. The luminance (reference value) when is 1 is obtained as shown in (V). The luminance ratio shown in (V) is none other than the ratio of the five primary colors for displaying negative gray levels. From the value shown in (V), it can be seen that as the absolute value of the level of the blue component NB increases, the luminance of yellow as a complementary color increases and the luminance of the other primary colors decreases. Since the sign of the level of the blue component NB when performing the linear combination is negative, the value shown in (VI) is obtained by inverting the sign of the value shown in (V), and the coefficient for the blue component NB in the negative level It can be. In this way, the coefficient for the blue component NB at the negative level (coefficient for linear coupling) can be obtained.

[0089] In the above description, the level of each color component of the input RGB signal is assumed from the chromaticity and brightness when only the yellow sub-pixel is fully lit, and the coefficient for the blue component NB However, of course, the coefficient for the blue component NB can be back calculated from the chromaticity and brightness of the color displayed in other lighting states.

[0090] As can be seen from FIGS. 11 and 12, although the value of the NB coefficient differs depending on the calculation method, yellow as a complementary color shows a negative value, and colors other than the complementary color show a positive value. Have the same power.

 In other words, from another viewpoint, the present invention relates to the phenomenon that the saturation of the complementary color side increases and the overall luminance decreases due to the fact that a signal of a primary color shows a negative value from 0. In order to solve simultaneously, it can be seen that this is a means of increasing the brightness of the primary colors of the complementary colors while lowering the brightness of the primary colors other than the complementary colors. Therefore, as long as such a signal can be generated, the calculation method introduced in the description of the present embodiment is not necessarily required.

 Note that the generated five primary color signals may be input to the multi-primary color panel 120 after performing gamma correction.

 In the above description of the embodiment, the display device that converts the three primary color signals into the five primary color signals and displays them is exemplified, but the number of primary colors employed in the present invention is not limited to these. The present invention receives m primary signals corresponding to m primary colors (m is smaller than n! /, A natural number), and n primary color signals corresponding to n primary colors (n is a natural number of 4 or more). Applies to display devices that convert to and display. For example, the present invention is also applied to a display device that converts and displays three primary color signals into six primary color signals.

 Further, the present invention is also applied to a field sequential drive type display device.

 Note that the components of the display device 100 described above can be realized by hardware, and some or all of them can also be realized by software.

 [0096] When these components are realized by software, they may be configured by a computer, and this computer executes a CPU (central processing unit) for executing various programs and these programs. RAM (random access memory) that functions as a work area. Then, a program for realizing the function of each component is executed on the computer, and this computer is operated as each component.

[0097] Further, the program may be supplied from a recording medium to a computer or may be a communication. It may be supplied to the computer via a network.

 [0098] The recording medium may be configured so as to be separable from the computer or may be incorporated in the computer. This recording medium can be read via a program reading device connected to the computer as an external storage device even if the recording program code is attached to the computer so that the computer can directly read the recorded program code. Even if it is something that is worn like

 [0099] Examples of the recording medium include tapes such as magnetic tapes and cassette tapes: magnetic disks such as flexible disks / hard disks, magneto-optical disks such as MO and MD, and optical disks such as CD-ROM, DVD and CD-R. Disk: IC card (including memory card), optical card, etc .: Or semiconductor such as mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash ROM A memory or the like can be used.

 [0100] When a program is supplied via a communication network, the program takes the form of a carrier wave or a data signal in which the program code is embodied by electronic transmission.

Industrial applicability

[0101] The present invention is suitably used for various display devices, such as a liquid crystal display device, a CRT (brown tube), an organic EL display device, a plasma display panel, and a surface-conduction electron-emitter display (SED). Is preferably used.

Claims

The scope of the claims  [1] A display device that performs display using n (n is a natural number of 4 or more) primary colors,  A video signal conversion unit that receives m primary color signals corresponding to m primary colors (m is smaller than n! /, a natural number) and converts the m primary color signals into n primary color signals corresponding to the n primary colors is provided. The n primary colors include a primary color complementary to a certain primary color among the m primary colors,  When the color component corresponding to the one primary color of the m primary color signals is at a negative level, the video signal conversion unit is more than the case where the color component corresponding to the one primary color is zero. A display device that generates the n primary color signal so that the luminance of a primary color having a complementary color relationship is high and the luminance of a primary color other than the primary color having a complementary color relationship is low.  [2] The video signal conversion unit generates a color conversion color signal by performing color conversion of the m primary color signal, and linearly combines each color component of the color conversion color signal to thereby convert the n primary color signal. The display device according to claim 1, wherein each color component is generated.  [3] The color matching conversion color signal includes a color component corresponding to the one primary color,  The color component corresponding to the one primary color is assigned a coefficient used for the primary combination to each of the n primary colors! /,  Among the coefficients assigned to the color component corresponding to the one primary color, the coefficient for the primary color having the complementary color relationship and the coefficient for the primary color other than the primary color having the complementary color relationship are mutually positive and negative. The display device according to claim 2, wherein the signs are different.  4. The display device according to claim 1, wherein the video signal conversion unit generates the color components of the n primary color signals by linearly combining the color components of the m primary color signals.  [5] The color component corresponding to the one primary color is assigned a coefficient used for the primary combination to each of the n primary colors! /,  Among the coefficients assigned to the color component corresponding to the one primary color, the coefficient for the primary color having the complementary color relationship and the coefficient for the primary color other than the primary color having the complementary color relationship are mutually positive and negative. The display device according to claim 4, wherein the signs are different. [6] comprising a pixel including a plurality of sub-pixels; The display device according to claim 1, wherein each of the plurality of sub-pixels displays a corresponding one of the n primary colors. 7. The display device according to claim 1, wherein the one primary color is red and the primary color complementary to the one primary color is cyan. 8. The display device according to claim 1, wherein the one primary color is green, and the primary color complementary to the one primary color is magenta. 9. The display device according to claim 1, wherein the one primary color is blue, and a primary color complementary to the one primary color is yellow. 10. The display device according to claim 1, wherein n is 5 and m is 3. [11] The five primary colors are red, yellow, green, cyan, and blue.  When the color component corresponding to red in the five primary color signals is at a negative level, the video signal converter has a relationship between the red color and the complementary color more than when the color component corresponding to red is zero. 11. The display device according to claim 10, wherein five primary color signals are generated so that a certain cyan luminance is increased and a luminance of primary colors other than cyan is decreased. [12] The five primary colors are red, yellow, green, cyan, and blue.  When the color component corresponding to blue in the five primary color signals is at a negative level, the video signal conversion unit has a relationship between the blue and the complementary color more than when the color component corresponding to blue is zero. 11. The display device according to claim 10, wherein five primary color signals are generated so that a certain yellow luminance is increased and luminances of primary colors other than yellow are decreased. [13] A method for generating n primary color signals corresponding to the n primary colors for display using n primary colors (n is a natural number of 4 or more),  The method includes a conversion step of receiving m primary color signals corresponding to m primary colors (m is less than n! /, A natural number) and converting the m primary color signals into the n primary color signals,  The n primary colors include primary colors that are complementary to one primary color among the m primary colors, In the converting step, when the color component corresponding to the certain primary color of the m primary color signals is at a negative level, the conversion step is more than when the color component corresponding to the certain primary color is zero. The primary color that is in a complementary color relationship has a high luminance and is in the complementary color relationship. A method comprising the step of generating the n primary color signal in which the luminance of primary colors other than the primary color is lowered.  [14] A program for causing a computer to execute generation processing for generating n primary color signals corresponding to the n primary colors for display using n primary colors (n is a natural number of 4 or more). ,  The generation processing includes a conversion step of receiving m primary color signals corresponding to m primary colors (m is smaller than n! /, A natural number), and converting the m primary color signals into the n primary color signals. Includes primary colors that are complementary to one of the m primary colors,  In the converting step, when the color component corresponding to the certain primary color of the m primary color signals is at a negative level, the conversion step is more than when the color component corresponding to the certain primary color is zero. A program including the step of generating the n primary color signal so that the luminance of a primary color having a complementary color relationship is increased and the luminance of a primary color other than the primary color having a complementary color relationship is decreased.